An approximate true damping solution of the flutter equation by determinant iteration.

Abstract

The difference between a true damping, or rate-of-decay, solution of the flutter equation and the structural-damping-type of solution is highlighted. True damping solutions are possible if unsteady aerodynamics can be expressed in terms of the complex variable p. If the aerodynamics are given at discrete values of the reduced frequency fc, an approximate determination of the true damping is possible by assuming that the aerodynamic forces for harmonic motion are a good approximation for the cases of slowly increasing or decreasing amplitude. A determinant iteration method for obtaining the solution is presented. Results obtained by different methods of solving the flutter equation are compared.